DUT testing systems often require a very cold cooling fluid during testing. The cooling fluid can be obtained from a refrigeration system. Typical refrigeration systems used for DUT testing are configured to operate only in a single mode which provides maximum cooling to the cooling fluid. If maximally cooled fluid is not needed for the DUT testing system, the fluid is then reheated to a desired temperature. For example, if the refrigerant system cools the fluid to −90 degrees Celsius, and a fluid of −40 degrees Celsius is required for the DUT testing system, the fluid will be heated from −90 degrees Celsius to −40 degrees Celsius after leaving the refrigerant system and before entering the DUT testing system. This method inherently demands energy, and energy is wasted as the fluid is cooled to an unnecessarily low temperature, only to be heated back up before being used.